WASHINGTON -- Following fast on the heels of armor thrusting into Kuwait and Iraq, a vast logistical train must head into the desert to feed, fuel and arm the immense attacking armies of the alliance.

Without this effort, the rapid progress reported from the war zone would quickly bog down as troops ran out of supplies, beginning with the fuel guzzled by tanks, helicopters and other heavy weapons.

The logistical plan, set up and rehearsed in detail for many weeks, has been made easier to carry out because the advance has met minimal initial resistance. As long as the advancing armies control the ground and the air along the lines of attack, their logistical trains will be relatively safe.

But paradoxically, the success of the attack so far has probably strained the logistical system, since the rapid advance means that large quantities of fuel have to be delivered over longer distances than expected.

To deliver the fuel, tanker trucks must race across the desert and transport aircraft must drop off bladders of fuel.

Special mobile pumping equipment, designed so that many vehicles can simultaneously replenish themselves, allows units to pull in and quickly get back into combat.

Eventually, pipelines may even be laid to speed the flow of fuel and to free trucks and aircraft for carrying ammunition instead.

The allies' main battle tanks, which are too big and heavy to be delivered by air, crossed the Saudi border carrying enough fuel to reach their first day's objectives deep in Iraq without refueling. They can go nearly 300 miles before refilling. But they measure their fuel consumption in gallons per mile, and every refill soaks up 498 gallons for their thirsty turbine engines.

When the heavy mechanized and armored divisions begin fighting deep in enemy territory, firepower replaces maneuver in importance, and ammunition rises to the top of the cargo manifests. A multiple rocket launcher, for instance, can shoot only one volley of 12 rockets before it must load a new box of armament onto its rack.

Finally, food and water rations have to be delivered after about three days, and the wounded and dead will have to be shipped out.

In some cases, logistical bases have been set up in advance of the ground forces, an example being the helicopter refueling base set up inside Iraq by the 101st Airborne Division. The base supports the 101st's own activities and could be used as TC forward gas station and ammunition dump for armored units approaching overland from the south.

But most combat units that enter Iraq or Kuwait must set up their own staging areas, usually only after the assault has already moved safely past.

The assaulting troops themselves carry a mix of supplies known as a "basic load," sometimes also called "a day of fire."

Behind every battalion, brigade and division in the battle is a logistical support unit dedicated to passing supplies forward. A 500-man mechanized battalion, for instance, has 12 heavy trucks attached to it. Those shuttle back and forth to fuel and ammunition depots 15 miles or so behind the main battle lines.

The battalion's depots would be supplied from larger ones established by the brigade commander further back, and he would get the brigade's supplies from the division's stocks, fed in turn from the corps's supplies back in the rear areas.